Oil-in-water emulsions

ABSTRACT

The present invention relates to oil-in-water emulsions comprising 0.001-70% by weight, preferably from 0.5 to 45% by weight, of at least one active substance from the class of the phosphates and/or carbamates, from 0.001-20% by weight, preferably from 0.1-10% by weight, of at least one salt of an aryl polyglycol ether phosphate of the formula I ##STR1## in which each R 1 , independently of the others, is hydrogen, C 1  -C 24  -alkyl, C 5  -C 15  -cycloalkyl, C 8  -C 24  -aryl or C 6  -C 24  -alkaryl, 
     R 2  is hydrogen, --O--C 1  -C 24  -alkyl, --O--C 5  --C 15  -cycloalkyl, --O--C 6  -C 18  -aryl or A, 
     M is an alkali metal ion, alkaline earth metal ion or ammonium ion of the formula HN(R 3 ) 3 , where each R 3 , independently of the others, is hydrogen, C 1  -C 4  -alkyl, C 5  -C 15  -cycloalkyl, C 6  -C 18  -aryl or a group of the formula --(CH 2 ) z  --OH in which z is a number from 1 to 10, x is a number from 0 to 80 and y is a number from 0 to 50, the sum of x and y not being zero, and, to make up to 100% by weight, water and, if desired, solvents and/or additives. These oil-in-water emulsions are preferably employed in agriculture and in horticulture, in the domestic and hygiene sectors and/or in the medical sector.

This application is a 35 USC 371 of PCT/EP93/03165 filed Nov. 11, 1993,published as WO94/10839 May 26, 1994.

The prior art already includes oil-in-water emulsions which containactive substances from the class of the phosphates and carbamates andwhich are employed in agriculture, in horticulture, in the domestic andhygiene sectors, and/or in the medical sector.

U.S. Pat. No. 4,107,302 discloses aqueous emulsion concentrates (EW)which, in addition to the organophosphorus active substance, forinsecticidal control, and the surfactant, additionally and compulsorilycontain an aqueous buffer solution for establishing a specific pH range.

EP-B-0 196 463 describes macroemulsions containing phosphates, in whichnonionic nonylphenol/propylene oxide/ethylene oxide adducts are used todisperse the active substance.

The oil-in-water emulsions known from EP-B-0 062 181 contain, inaddition to the active substances, as emulsifier at least one andgenerally two or more alkylaryl polyglycol ethers in a mixture withionic alkylarylsulfonic acid salts.

EP-B-0 289 909 discloses aqueous, phase-stable, homogeneous emulsioncompositions of organophosphorus pesticides, which contain, in additionto the active substance, a nonionic block copolymer, random copolymer,or random/block copolymer as surfactant and urea as a thickener andstabilizer.

EP-A-0 160 182 relates to aqueous microemulsions containing, in additionto a synthetic pyrethroid as active substance, an emulsifier mixturecomprising calcium dodecylbenzenesulfonate, ethoxylateddistyrylphenolammonium sulfate and ethoxylated tristyrylphenol.

In the emulsion concentrates (EC) described in GB-B-0 717 279 and U.S.Pat. No. 2,696,453, the quantity in which the active substances aredissolved in organic solvents (e.g. xylene, toluene, kerosene) andadmixed with an emulsifier mixture comprising a nonionic and an ionicsurfactant (polyoxyalkylene glycol/alkylarylsulfonate) ensures that,when these concentrates are diluted with water to the applicationconcentration, a sufficiently stable aqueous emulsion is formed. Onaccount of the solvents they contain, however, the concentrates areoften associated with disadvantages in respect of their combustibility,toxicological characteristics, tolerance by plants and odor.

The abovementioned aqueous emulsifiable concentrates (EW) can only beprepared using additional auxiliaries, such as a thickener, stabilizerand buffer, organic solvents, and surfactant mixtures based mostly onnonionic and ionic surfactants.

Oil-in-water emulsions in the form of aqueous emulsifiable concentrates(EW) have now been found which, in addition to active substances fromthe class of phosphates and/or carbamates, and water, compulsorilycontain at least one salt of an aryl polyglycol ether phosphate as ionicsurfactant. In this case, the use of organic solvents, nonionic/ionicsurfactant mixtures and/or additional auxiliaries, such as a thickener,stabilizer and buffer, is not compulsory.

It must be referred to as extremely surprising that the aqueousemulsifiable concentrates (EW) according to the invention are stable,since, on the basis of the known prior art, it was not to be expectedthat such emulsions, containing no thickener, stabilizer or buffer,little or no organic solvent and only one class of surfactant, arestable over a prolonged period.

The invention relates to oil-in-water emulsions comprising 0.001-70% byweight, preferably from 0.5 to 45% by weight, of at least one activesubstance from the class of the phosphates and/or carbamates, from0,001-20% by weight, preferably from 0.1-10% by weight, of at least onesalt of an aryl polyglycol ether phosphate of the formula I ##STR2## inwhich each R¹, independently of the others, is hydrogen, C₁ -C₂₄ -alkyl,C₅ -C₁₅ -cycloalkyl, C₆ -C₂₄ -aryl or C₆ -C₂₄ -alkaryl, R² is hydrogen,--O--C₁ -C₂₄ -alkyl, --O--C₅ -C₁₅ -cycloalkyl, --O--C₆ -C₁₈ -aryl or A,

M is an alkali metal ion, alkaline earth metal ion or ammonium ion ofthe formula HN.sup.⊕ (R³)₃, where each R³, independently of the others,is hydrogen, C₁ -C₄ -alkyl, C₅ -C₁₅ -cycloalkyl, C₆ -C₁₈ -aryl or agroup of the formula --(CH₂)_(z) --OH in which z is a number from 1 to10,

x is a number from 0 to 80 and y is a number from 0 to 50, the sum of xand y not being zero, and,

to make up to 100% by weight, water and, if desired, solvents and/oradditives.

The oil-in-water emulsions according to the invention contain at leastone agrochemical active substance, an active substance for controllingpests in the domestic and hygiene sectors and/or a pharmacologicallyactive substance from the class of the phosphates and/or carbamates.Suitable active substances include both those substances which areliquid at room temperature and those which are solid at roomtemperature. Such active substances are known and are described in "ThePesticide Manual", 9th edition, The British Crop Protection Council,1991.

In the present case, the agrochemical substances are to be understood asmeaning all active substances which can usually be used in cropprotection. These include, for example, insecticides, acaricides,nematicides, fungicides, herbicides, growth regulators and fertilizers.

Specific examples of such active substances are:

O,O-Diethyl O- 2-isopropyl-4-methyl-6-pyrimidinyl!thiophosphate(diazinon)

O,O-Diethyl O- 3,5,6-trichloro-2-pyridyl!thiophosphate (chlorpyrophos)

2-(1-Methylpropyl)phenyl methylcarbamate (BPMC)

O,O-dimethyl S-methylcarbamoylmethyl thiophosphate (dimethoate)

Chlorobicyclo 3.2.0!hepta-2,6-dien-6-yl phosphate (heptenophos)

O,O-Diethyl O-1-phenyl-1H-1,2,4-triazol-3-yl thiophosphate (triazophos)

Ethyl 2-diethoxyphosphinothioyloxy-5-methylpyrazolyl1,5-α!pyrimidine-6-carboxylate (pyrazophos)

O,O-Diethyl O-(4-nitrophenyl) thionophosphonate

O,O-Dimethyl O-(4-nitrophenyl) thionophsophate (fenitrothion)

O-Ethyl O-4-methylthiophenyl S-propyldithiophosphate

2-Isopropoxyphenyl N-methylcarbamate

2,3-Dihydro-2,2-dimethyl-7-benzofuryl methylcarbamate

3,5-Dimethyl-4-methylthiophenyl N-methylcarbamate

O,O-Diethyl O-(3-chloro-4-methyl-7-coumarinyl) thiophosphate

S- 1,2-bis(ethoxycarbonyl)ethyl!O,O-dimethyl dithiophosphate (malathion)

O,O-Dimethyl O-4-methylmercapto-3-methylphenyl thionophosphate(fenthion, Lebaycid)

O-Ethyl O-2-isopropyloxycarbonylphenyl N-isopropylthionophosphoramide.

In the present case, active substances for controlling pests in thedomestic and hygiene sectors are to be understood as all conventionalactive substances of low solubility in water. Specific examples of suchactive substances are:

2-Isopropoxyphenyl N-methylcarbamate

O,O-Diethyl-O-4-nitrophenyl thionophosphate (ethylparathion)

O,O-Dimethyl O-4-nitrophenyl thionophosphate (methylparathion)

S- 1,2-bis(Ethoxycarbonyl)ethyl!O,O-dimethyl dithiophosphate

O,O-Dimethyl O-3-methyl-4-nitrophenyl thionophosphate (sumithion,folithion)

O,O-Dimethyl O-4-methylmercapto-3-methylphenyl thionophosphate(Lebaycid, fenthion).

In the present case, pharmacologically active substances are to beunderstood as substances of low solubility in water which can preferablybe employed in the veterinary sector. An example of such activesubstances is chlorobicyclo 3.2.0!hepta-2,6-dien-6-yl phosphate(heptenophos).

The oil-in-water emulsions according to the invention contain at leastone salt of an aryl polyglycol ether phosphate of the formula I ##STR3##in which R¹, R², M, x and y have the aforementioned meaning.

The radicals R¹, R² and R³ may be substituted. Suitable substituents arehalogens such as bromine and chlorine, hydroxyl, nitro, amino, carboxyland sulfo or their ester group. Preferred compounds of this type arethose in which

R¹ is C₁ -C₆ -alkyl, phenyl, naphthyl, diphenyl, styryl or1-phenylethyl,

R² is C₁ -C₆ -alkyl, phenyl or A,

M is an alkali metal ion, a mono-, di- or triethylammonium ion or atriethanolammonium ion,

x is a number from 10 to 50, and

y is a number from 10 to 35.

Particularly preferred surfactants are potassium or triethylammonium2,4,6-tris(1-phenylethyl)phenol polyglycol ether monophosphatecontaining on average 20 EO units (EO=ethylene oxide), andtriethanolamine salts of a mixture of mono- and diphosphates of atristyrylphenol polyglycol ether containing on average from 18 to 20 EOunits.

The surfactants of the formula I are known but have previously beenemployed in formulations in combination with other surfactants. In thiscontext, reference is made to the following publications: EP-A-0 163598, EP-A-0 201 417, EP-A-0 364 328, EP-A-0 432 061, EP-A-0 432 062,DE-A-3 503 706, DE-A-3 542 440, DE-A-3 614 788 and DE-A-3 624 910.

The oil-in-water emulsions contain water as the continuous phase. Whereconcentrates are concerned, the amount of water is relatively low. Inthe case of heavily diluted emulsions, considerable quantities of waterare present. The oil phase (=disperse phase) is distributed in the formof droplets in the aqueous phase. The size of the oil droplets can inthis case be varied within a certain range. In general, the particlediameter is between 0.01 and 10 μm, preferably between 0.2 and 5.0 μm.In the oil-in-water emulsions according to the invention, the percentageproportions of the components they contain can be varied withinrelatively large ranges. The proportion of active substances from theclass of the phosphates and/or carbamates is in general between 0,001and 70% by weight, preferably between 0.5 and 45% by weight. Theproportion of surfactant of the formula I is in general from 0,001 to20% by weight, preferably from 0.1 to 10% by weight.

Furthermore, these oil-in-water emulsions contain only a very smallquantity of organic solvents, or even none at all. They are thereforenot combustible, are virtually or totally free of the odor problemscaused by organic solvents, and in general have a lower toxicity andphytotoxicity than corresponding formulations which contain organicsolvents at the concentrations which are otherwise usual. Suitableorganic solvents which they may, if appropriate, contain are allconventional organic solvents or solvent mixtures which are of lowmiscibility with water and which boil at between 100° C. and 290° C.Preferred such solvents are aromatic hydrocarbons such as xylene,toluene, ethylbenzene, alkylated benzenes containing on average 9 carbonatoms, such as the solvent grades known under the name Solvesso® (EssoChemic GmbH) and dimethylnaphthalene, and halogenated aromatichydrocarbons such as chlorobenzenes, aliphatic hydrocarbons such asbenzine and petroleum ether, cycloaliphatic hydrocarbons such ascyclohexane, and alcohols and ketones, such as n-butanol, n-hexanol,iso-hexanol, n-octanol, cyclohexanol, benzyl alcohol and di-n-butylketone, and also ethers and esters.

The content of organic solvents is in general from 0-50% by weight,preferably from 0-20% by weight, based on the emulsion.

Additives which the oil-in-water emulsions according to the inventionmay suitably contain are preservatives, antifreezes, dyes andodor-improvers.

Examples of preservatives are 2-hydroxybiphenyl, sorbic acid,p-hydroxybenzaldehyde, methyl p-hydroxybenzoate, benzaldehyde, benzoicacid, propyl p-hydroxybenzoate and p-nitrophenol. The content ofpreservative in the emulsion is between 0.01 and 1% by weight.

Suitable antifreezes are glycol, glycerol, polyethylene glycol, sugarand salts such as ammonium sulfate and sodium oleate, of which theemulsions usually contain from 1 to 10% by weight.

Examples of dyes which may be mentioned are azo dyes and phthalocyaninedyes. Perfume oils can be employed as odor-improvers.

An appropriate preparation process is described in EP-B-0 130 370.

In addition to the advantages already mentioned in connection with thelow content of organic solvents, the oil-in-water emulsions are alsonotable for their stability under practical conditions. On long termstorage both at high temperatures (50° C.) and at low temperatures (-5°C., -10° C.), these emulsions remain unchanged with respect to theirphysical stability and their content of active substance. An additionaladvantage is that active substances can be emulsified equally wellwhether they are solid or liquid at room temperature.

The oil-in-water emulsions according to the invention can be appliedeither as formulated or after previous dilution. The application ratedepends on the concentration of the oil-in-water emulsion and on theparticular indication.

The emulsions are applied by the conventional methods; that is, forexample, by spraying or pouring.

The formulation examples given in the following Tables are evidence ofthe broad range of application. ®Solvesso 150 (Esso Chemie GmbH):boiling range 186°-205° C., aromatic content 99%.

Surfactant 1: triethanolamine salt of a mixture of mono- anddiphosphates of 2,4,6-tris(1-phenylethyl)phenol polyglycol ethercontaining on average 20 EO units.

Surfactant 2: triethanolamine salt of the monophosphate of2,4,6-tris(1-phenylethyl)phenol polyglycol ether containing on average20 EO units.

Surfactant 3: tristyrylphenol containing on average 20-26 EO units.

Table 1 shows oil-in-water emulsions according to the invention whichare stable over a period of at least three months (storage temperature:25° C.; 50° C.).

Table 2 shows, as comparative examples, oil-in-water emulsionscontaining a nonionic surfactant (tristyrylphenol containing 20 mol ofEO) and an ionic surfactant (calcium phenylsulfonate). In theseemulsions, the active substance is substantially broken down (>10% byweight) after only 2 weeks (storage temperature: 25° C.; 50° C.).

                                      TABLE 1                                     __________________________________________________________________________            Examples; components in % by weight; water to 100% by weight                  1   2   3    4   5   6   7    8   9   10  11  12   13                 __________________________________________________________________________    Surfactant 1                                                                               7   5                5                                           Surfactant 2                                                                           7           10   7   4        5   7  10   5   3    3                 Xylene  20  20  10       20  20  20   20  20  20  20  20   20                 ® Solvesso 150                                                                            10                                                            Malathion                                                                             42  42  42   42                                                       Ethyl-                   51  51  51   51                                      parathion                                                                     Fenitrothion                              41.7                                                                              42  52                          Diazinon                                              52   52                 Temperature                                                                           -5 to                                                                             -5 to                                                                             -5 to                                                                              -5 to                                                                             -5 to                                                                             -5 to                                                                             -5 to                                                                              -5 to                                                                             -5 to                                                                             -5 to                                                                             -5 to                                                                             -5                                                                                 -5 to              stability                                                                             50° C.                                                                     50° C.                                                                     50° C.                                                                      50° C.                                                                     50° C.                                                                     50° C.                                                                     50° C.                                                                      50° C.                                                                     50° C.                                                                     50° C.                                                                     50° C.                                                                     50° C.                                                                      50°         __________________________________________________________________________                                                               C.                         Examples; in % by weight; water to 100% by weight                             14   15   16   17   18   19   20   21   22   23   24                  __________________________________________________________________________    Surfactant 1                           7    7    7    7    7                  Surfactant 2                                                                           7    7    4    3    7    5                                           Xylene  35   35   20   20   20   10   18   32    5   20   26                  ® Solvesso 150               10                                           Malathion                                            42                       Chlorpyrophos                                                                         24   24                                                               Fenthion          52.4 52.4                                                   BPMC                        50   50                                           Heptenophos                                     54                            Triazophos                                                40                  Pyrazophos                            15   26                                 Antifreeze                            10   10   10        10                  Temperature                                                                           -5   -5   -5   -5   -5   -10  -10  -10  -10  -5   -10                 stability                                                                             to 45° C.                                                                   to 45° C.                                                                   to 50° C.                                                                   to 50° C.                                                                   to 40° C.                                                                   to 40° C.                                                                   to 50° C.                                                                   to 50° C.                                                                   to 40° C.                                                                   to 50°                                                                      to 40°       __________________________________________________________________________                                                              C.              

                  TABLE 2                                                         ______________________________________                                                     Examples; % by weight;                                                        water to 100% by weight                                          Composition    V1     V2        V3   V4                                       ______________________________________                                        Surfactant 3                    7.5                                           ® Emulsogen EL 400                                                                       8      7                                                       Ca phenylsulfonate                                                                           4      4         1.5  11.2                                     ® Emulsogen 3510                 13.8                                     Xylene         20     20                                                      Malathion                            52.6                                     Diazinon                        61.7                                          Heptenophos    30     25                                                      Temperature stability                                                                        ./.    ./.       ./.  ./.                                      ______________________________________                                    

We claim:
 1. An oil-in-water emulsion comprising0.001-70% by weight ofat least one liquid active substance, said active substance being aphosphate or carbamate or mixture thereof; from 0.001-20% by weight, ofemulsifier consisting essentially of at least one salt of an arylpolyglycol ether phosphate of the formula I ##STR4## in which each R¹,independently of the others, is an unsubstituted or substitutedC₁ -C₂₄-alkyl, C₅ -C₁₅ -cycloalkyl, C₈ -C₂₄ -aryl or C₆ -C₂₄ -alkaryl group; R²is hydrogen or is an unsubstituted or substituted --O--C₁ -C₂₄ -alkyl,--O--C₅ -C₁₅ -cycloalkyl, --O--C₆ -C₁₈ -aryl or A group, where A is theA group of said formula I, M is an alkali metal ion, alkaline earthmetal ion or ammonium ion of the formula HN(R³)₃, where each R³,independently of the others, is hydrogen or is an unsubstituted orsubstituted C₁ -C₄ -alkyl, C₅ -C₁₅ -cycloalkyl, C₆ -C₁₈ -aryl, or--(CH₂)_(z) --OH group, in which z is a number from 1 to 10; x is anumber from 0 to 80 and y is a number from 0 to 50, the sum of x and ynot being zero, and sufficient water to provide an oil-in-water emulsionwith an aqueous phase as the continuous phase.
 2. An emulsion as claimedin claim 1, wherein said emulsion comprises, to make up 100% by weight,water and optionally at least one solvent and at least one additive. 3.An emulsion as claimed in claim 1, wherein said emulsion furthercomprises at least one additional active substance which isagrochemically active or is active for controlling pests.
 4. An emulsionas claimed in claim 1, wherein said active substance ispharmacologically active.
 5. An emulsion as claimed in claim 1, whereinthe salt of an aryl polyglycol ether phosphate is a mono- or diphosphateof a phenol polyglycol ether or a mixture thereof.
 6. An emulsion asclaimed in claim 1, which contains from 0-50% by weight, based on theemulsion, of an organic solvent.
 7. An emulsion as claimed in claim 6,wherein said organic solvent is an aromatic, aliphatic or cycloaliphatichydrocarbon or an alcohol or ketone.
 8. An emulsion as claimed in claim6, wherein the amount of organic solvent does not exceed 20% by weight,based on the emulsion.
 9. An emulsion as claimed in claim 1, whereinsaid emulsion is essentially free of organic solvent.
 10. An emulsion asclaimed in claim 1, which emulsion further comprises at least oneadditive, said additive being a preservative, an antifreeze, anodor-improver or an acid.
 11. An emulsion as claimed in claim 1, whereinthe oil phase of the oil-in-water emulsion is distributed in saidaqueous phase in the form of drops having an average particle diameterof between 0.01 and 10 μm.
 12. An emulsion as claimed in claim 11,wherein said average particle diameter is in the range of 0.2 to 0.5 μm.13. An emulsion as claimed in claim 1, wherein the emulsion consistsessentially of:0.5 to 45% by weight of a said active substance, 0.1-10%by weight of at least one said salt of an aryl polyglycol etherphosphate, and to make up 100% by weight, water and, optionally, atleast one additive or solvent; said emulsion being essentially free ofany thickener, stabilizer, or buffer.
 14. A method for treating plantscomprising the step of applying to said plants an emulsion as claimed inclaim
 1. 15. A method for controlling pests comprising the step oftreating the pests with an emulsion as claimed in claim
 1. 16. Anoil-in-water emulsion comprising0.001-70% by weight of at least oneliquid active substance, said active substance being a phosphate or acarbamate or a mixture thereof, sufficient water to form saidoil-in-water emulsion, from 0.001-20% by weight, of at least one salt ofan aryl polyglycol ether phosphate of the formula I ##STR5## in which Arepresents the radical set forth within the brackets in the foregoingformula I,each R¹, independently of the others, is C₁ -C₂₄ -alkyl, C₅-C₁₅ -cycloalkyl, C₈ -C₂₄ -aryl or C₆ -C₂₄ -alkaryl, R² is hydrogen,--O--C₁ -C₂₄ -alkyl, --O--C₅ -C₁₅ -cycloalkyl, --O--C₆ -C₁₈ -aryl or A,M is an alkali metal ion, alkaline earth metal ion or ammonium ion ofthe formula HN(R³)₃, where each R³, independently of the others, ishydrogen, C₁ -C₄ -alkyl, C₅ -C₁₅ -cycloalkyl, C₆ -C₁₈ -aryl, or a groupof the formula --(CH₂)_(z) --OH in which z is a number from 1 to 10; xis a number from 0 to 80, and y is a number from 0 to 50, the sum of xand y not being zero.
 17. An emulsion as claimed in claim 16, whereinsaid emulsion comprises, to make up 100% by weight, water and optionallyat least one solvent and at least one additive.
 18. An emulsion asclaimed in claim 1, wherein said emulsion further comprises at least oneadditional active substance which is agrochemically or pharmacologicallyactive or is active for controlling pests.